# Slow date\_histogram after upgrading to 7.8.0

**URL:** <https://discuss.elastic.co/t/slow-date-histogram-after-upgrading-to-7-8-0/244404>\
**Category:** Elasticsearch\
**Created:** [August 10, 2020, 1:02pm UTC](https://discuss.elastic.co/t/slow-date-histogram-after-upgrading-to-7-8-0/244404 "2020-08-10T13:02:02Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Chan\_Terence](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/chan_terence/32/47277_2.png) [@Chan\_Terence](https://discuss.elastic.co/u/Chan_Terence)\
**Post date:** [August 10, 2020, 1:02pm UTC](https://discuss.elastic.co/t/slow-date-histogram-after-upgrading-to-7-8-0/244404/1 "2020-08-10T13:02:02Z")

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Hi there,

We noticed a serious performance degradation of date\_histogram aggregations on our cluster after upgrading to 7.8.0.  
We have two indexes with 1.2billion documents and use only date\_histogram, but this query need 10S.  
We use Profiler api to generate the following result.

> **[profile.txt](https://drive.google.com/file/d/1n7z-58eUYShkWlHkJp8ehwnBKdvCENIj/view?usp=sharing)**
>
> Google Drive file.

We have 14 machines , per node has 128G memory and 5T SSD disk。

Did someone experienced the same behaviour?Is this something we can tune?

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**Author:** ![polyfractal](https://sea2.discourse-cdn.com/elastic/user_avatar/discuss.elastic.co/polyfractal/32/48162_2.png) [@polyfractal](https://discuss.elastic.co/u/polyfractal)\
**Post date:** [August 12, 2020, 1:33pm UTC](https://discuss.elastic.co/t/slow-date-histogram-after-upgrading-to-7-8-0/244404/2 "2020-08-12T13:33:51Z")

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Hiya @Chan_Terence! We've been making some changes recently to aggregations, date\_histo included. But the changes have all been performance optimizations for the most part... we've not seen any large regressions so far. But perhaps you've stumbled into an edge-case or something.

What was the performance like before upgrading? Is the upgrade the only thing that has changed recently?

Thanks for the profiler output! Would it be possible to also capture a [HotThreads API output](https://www.elastic.co/guide/en/elasticsearch/reference/current/cluster-nodes-hot-threads.html) while the query is running? That'll give us a glimpse into what's going on internally

Make sure it runs _without_ profiling enabled... profiling adds a fair amount of overhead and can skew hot thread outputs.

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**Author:** ![system](https://us1.discourse-cdn.com/elastic/original/3X/1/a/1ac57faf039f6b580b3f104ef42a2a89e41014de.png) [@system](https://discuss.elastic.co/u/system)\
**Post date:** [September 9, 2020, 1:33pm UTC](https://discuss.elastic.co/t/slow-date-histogram-after-upgrading-to-7-8-0/244404/3 "2020-09-09T13:33:54Z")

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